The present invention concerns movable or fixed apparatuses for raising objects or people vertically, and in particular movable devices used at airports for giving access to airplanes for loading or unloading, the apparatus of the invention being of the type using two support arms articulated together in the form of scissors.
Prior art apparatuses of this type are constituted by a platform or a cabin connected to a chassis which is generally movable, and raisable with respect to the latter by means of support arms articulated together to constitute Nuremberg scissors, and opening out under the action of hydraulic actuators. In this way, the platform or the cabin can be raised to a certain height while remaining parallel to itself during raising.
These known devices present some disadvantages, including the following:
(1) The connections of the support arms to the chassis and the platform are complex, one of the points of support having to be displaced with respect to these during raising, because the limbs of the Nuremberg scissors system are of fixed length.
(2) When the elevation is such that it necessitates several pairs of superposed scissors, the resulting multiplication of articulations involves multiplied working clearances and is very complex to achieve.
(3) With such devices, it is impossible to obtain a translatory movement of the cabin or platform without moving the carrier chassis.